This is an application to develop and evaluate an integrated psychosocial treatment (PST) for Attention-Deficit/Hyperactivity Disorder, Predominantly Inattentive type (ADHD-I). ADHD-I is a highly prevalent and serious childhood psychiatric disorder with significant academic and social impairment Children with ADHD-I differ from those with the well-studied ADHD-Combined Type (ADHD-C) in that they have maladaptive levels of inattention, but fewer problems of hyperactivity, impulsivity and antisocial behavior. Recent work also suggests unique cognitive problems in ADHD-I characterized by a sluggish cognitive tempo. No empirical studies of psychosocial interventions with ADHD-I are available, although these interventions may be the first line of treatment for ADHD cases without severe hyperactivity/impulsivity or comorbid disruptive behavior disorders, such as those with ADHD-I. The specific aims are to: (1) Develop a manualized psychosocial intervention for ADHD-I aimed at reducing symptom severity and functional impairment across multiple domains (e.g., academic, social, family, other externalizing and internalizing psychopathology); (2) Pilot the intervention through an open trial (N=12) and modify it as needed based on clinical outcomes and feedback from participants, clinicians, and study investigators; (3) Utilize the modified treatment manual in an initial randomized clinical trial of children diagnosed with ADHD-I (N=60), including a treated group and a community control group, to evaluate the short-term efficacy of the intervention; (4) Examine the durability of treatment gains at 2-month follow-up. The long-terms aims are to apply the treatment in larger-scale randomized trials including comparisons with stimulant medication and multimodal treatment combinations. The proposed treatment emphasizes practicality, ease of replication, and generalizability, important to our additional long-term plans of studying the treatment's effectiveness in the community and disseminating the intervention to schools and mental health practitioners. We also anticipate obtaining information, based on individual response to treatment, to further our understanding of ADHD-I.